NiFe layered double hydroxides (LDH) have been intensively investigated as promising electrocatalysts for oxygen evolution reaction. However, their hydrogen evolution reaction (HER) and overall water splitting performance are not satisfactory. Herein, we report a facile cation doping combined with plasma reduction strategy to generate heterostructured Ni nanoparticles/V-doped NiFe LDH nanosheet array with multiple vacancies, exhibiting excellent HER performance with a small overpotential of 19 mV at 10 mA cm^-2. Moreover, when evaluated as bi-functional electrocatalyst for overall water splitting, a small cell voltage (1.43 V at 10 mA cm^-2) and ultralong stability (over 1000 h) are achieved. Density functional theory (DFT) calculations reveal that V-doping, oxygen vacancy (O_v), Ni vacancy (Ni_v), and Ni nanoparticles can effectively improve the conductivity and optimize the hydrogen adsorption, O_v, Ni_v, and Ni nanoparticles help to facilitate H₂O adsorption and dissociation progress in HER, the V-doping and O_v can efficiently reduce the energy barrier of O* in OER, and Ni/NiFe LDH heterostructure ameliorates the electronic structure and tunes electron transfer route.

NiFe层状双氢氧化物（LDH）已被广泛研究为氧释放反应的有前途的电催化剂。然而，它们的放氢反应（HER）和总的水分解性能并不令人满意。在本文中，我们报道了一种简便的阳离子掺杂与等离子体还原策略相结合的方法，以产生具有多个空位的异质结构Ni纳米颗粒/ V掺杂NiFe LDH纳米片阵列，表现出出色的HER性能，在10 mA cm ^-2下具有19 mV的小过电位。此外，当评估为用于整体水分解的双功能电催化剂时，可实现较小的电池电压（10 mA cm ^-2时为1.43 V ）和超长稳定性（超过1000小时）。密度泛函理论（DFT）计算显示V掺杂，氧空位（O_v），Ni空位（Ni _v）和Ni纳米粒子可有效提高电导率并优化氢吸附，O _v，Ni _v和Ni纳米粒子有助于促进HER中的H ₂ O吸附和离解进展，V掺杂和O _v可以有效减少的O *在OER的能量势垒，以及Ni / LDH的NiFe异质结构改善了电子结构和曲调的电子转移的路线。